Ischemic diseases are significant causes of mortality in industrialized nations. It is well established that tissue damage results from ischemia (stoppage of blood flow to the tissue) followed by reperfusion of the tissue. The ischemic injury with the consecutive reperfusion is responsible for the disturbance of microcirculation with ensuing tissue damage and organ dysfunction.
One well-known example of ischemia and its effects is stroke, which is a condition resulting from a reduction or blockage of blood flow to the brain (cerebral ischemia). About 500,000 Americans suffer strokes each year, 80% of which are caused by a blood clot blocking one of the cerebral blood vessels. Symptoms of stroke include weakness, numbness or paralysis of the face, arm or leg; sudden loss or dimness of vision; loss of speech or difficulty using or understanding language; sudden, severe unexplained headache; or unexplained dizziness, unsteadiness or sudden falls (particularly if associated with one of the above symptoms).
Other organs are also affected by ischemia. For example, tissues such as kidney, heart, liver, pancreas, lung, intestine, are also known to sustain damage following ischemia and reperfusion.
The phosphorylation of ERK/MAP kinase in response to brain ischemia has been demonstrated previously. However, it is not known what, if any, role the ERK/MAP kinase pathway plays in the causation of tissue damage following ischemia and/or reperfusion.